31.—(1) Every employer, on making during any tax year to any earner any payment of emoluments in respect of which minimum payments are payable, may deduct minimum payments in accordance with this regulation.
(2) An employer shall not be entitled to recover any minimum payments paid or to be paid by him on behalf of any earner otherwise than by deduction in accordance with this regulation.
(3) Subject to the provisions of paragraph (4), on making any payment of emoluments to the earner the employer may deduct from those emoluments an amount which bears the same ratio to the amount of the minimum payments relating to those emoluments as A does to A plus B, where—
(a)A is the appropriate flat-rate percentage for primary Class 1 contributions specified in an order made under section 42B of the 1993 Act(1); and
(b)B is the appropriate flat-rate percentage for secondary Class 1 contributions specified in that order.
(4) Where two or more payments of emoluments fall to be aggregated under or by virtue of paragraph 1(1) of Schedule 1 to the Contributions and Benefits Act, the employer may deduct the amount of the minimum payments based thereon which are payable by the earner either wholly from one such payment or partly from one and partly from the other or any one or more of the others.
(5) In the circumstances specified in paragraph (6), if the employer on making any payment of emoluments to an earner does not deduct therefrom the full amount of minimum payments which by virtue of these Regulations he is entitled to deduct, he may recover the amount so underdeducted by deduction from any subsequent payment of emoluments to that earner during the same tax year, so however that any amount deducted under this paragraph may be in addition to, but shall not exceed, any amount deducted from the same payment of emoluments under paragraphs (3) or (4).
(6) Paragraph (5) applies only where—
(a)the underdeduction occurred by reason of an error made by the employer in good faith; or
(b)the emoluments in respect of which the underdeduction occurred are deemed to be earnings by virtue of regulations made under section 112 of the Contributions and Benefits Act; or
(c)the underdeduction occurred as a result of the variation of the contracting-out certificate issued in respect of the employment in respect of which the payment of emoluments is made; or
(d)the emoluments in respect of which the underdeduction occurred are, by virtue of regulation 17B of the Social Security (Contributions) Regulations 1979(2), not paid through the secondary contributor in relation to the employment.